ap stats unit 12

give the standard error of the slope in context

If we repeated the random assignment many times, the slope of the sample regression line would typically vary by about (SEb value) from the slope of the true regression line for predicting (context)

formula for confidence interval of slope B

b ± t*SEb

formula for standard error of slope B

SEb = s / (sx)√(n-1)

SEb

describes how far the sample slope typically varies from the population (true) slope in repeated random samples or random assignments

t* on calculator

4: invT
df = n-2

confidence interval: 2 tailed (divide by 2)

confidence interval for slope on calculator

STAT → TESTS LinRegTint

x values → L1

y values → L2

significance test for slope on calculator

STAT → TESTS → LinRegTest

x values → L1

y values → L2

power model transformations

^y =ax^(b)

1. plot y v.s. x^(p)

2. plot ^(p)√(y) v.s. x

3. plot log(x) v.s. log(y)

transformations of an exponential model

y^=ab^(x)

1. plot log(y) v.s. x

2. plot ln(y) v.s. x

Ho: B=0

Ha: B<0

Interpret the P-value

“if there is no linear relationship between the (x variable) and the (y variable), the probability of getting a random sample of (# in random sample) that yields a least-squares regression line w/ a slope of (slope) or less is (P-value)”

slope interpretation

for each one unit increase in x, y increases by (#) units